1. Field of the Invention
The present invention relates to systems, processes, and methods for making cheese products. More particularly, the present invention relates to a system and method for making cheese products which are enhanced to have a particular characteristic, such as increased yield, recovery of whey cream, desired protein content, water content, flavor, resistance to spoilage, accelerated ripening, or reduced, light, low fat, or fat free cheese, and Instant Quick Frozen Pizza cheese.
2. State of the Art
The making of cheese is generally a labor-intensive process that requires large quantities of milk to develop any of the many popular varieties. Typically, cheese yields range from 6% to 12% depending upon the variety and moisture content of cheese. The remainder of the milk forms by-products. Whey is the single largest product from the milk during the cheesemaking process and, prior to the present invention, has often been viewed as a negative by-product.
Numerous steps are required to turn milk into cheese having the desired characteristics of color, body, texture and organoleptic properties. Many of these steps are highly labor intensive and limit the speed and cost at which cheese can be produced. Additionally, success or failure in the market place is often determined by a company's ability to create cheese with the proper body, texture and organoleptic properties at the most competitive price. Because of the highly competitive nature of the cheese making industry, price differences of less than one cent per pound can provide significant advantages in the market place.
One significant concern that must be addressed for a cheese maker to be profitable is disposal of the by-products created during the cheese making process. For example, the formation of some types of cheese requires that the cheese be soaked in a brine solution. The brine solution quickly becomes contaminated with the cheese and the resulting breakdown products, primary free fatty acids and proteins. The resulting breakdown products of the cheese promote bacterial growth in the brine, which leads to contamination of the finished cheese. Further, the salt brine dissolves some of the cheese that leads to loss of yield.
Once the bacterial growth has reached certain levels, the contaminated brine solution must be discarded. The contaminated brine solution, however, must be specially handled in such a manner that it will not contaminate water supplies and or cause other environmental damage. Disposal of the brine solution is currently a major problem in the mozzarella industry and has forced some plants to close due to environmental concerns. Other cheeses that typically are brined include Brick, Romano, Parmesan, Blue, Swiss, etc. Disposal of the brine solution causes considerable problems in these portions of the cheese industry as well.
Another significant concern that must be addressed by nearly all cheese makers is disposal of cheese whey that is released during the cheese making process. As mentioned above, cheese whey is the largest product of the cheese making process. Cheese whey is a watery substance that contains large amounts of whey protein and lactose, which cannot be coagulated out of milk by typical coagulating enzymes or acid precipitants. Cheese whey contains approximately 0.9 percent whey protein and 5 percent lactose. About 25 percent of the total protein in milk is whey protein. Thus, disposal of cheese whey can be a significant problem.
Numerous attempts have been made to reintroduce the whey protein into cheese to eliminate disposal concerns and to enhance the protein content of the cheese and the yield. For example, in accordance with one method, whey protein extracted from one batch of milk during the cheese making process is returned to a subsequent batch of milk in an attempt to coagulate the whey protein with the cheese curds. Such attempts, however, have been relatively unsuccessful. Typically no more than about 18 percent of the whey protein reintroduced into the milk will precipitate out with the cheese curds. Several methods and procedures have been developed and patented over the years that primary utilize denatured whey protein in combination with caseins to form co-precipitates that have a propensity to precipitate out of the vat milk with the cheese curd. The efficiency of these processes and the effect upon the finished cheese is varied and none has achieved desired levels of whey precipitation. Thus, the remaining whey protein must be used for other purposes or disposed of in an appropriate manner.
One major problem with denaturing whey protein to the degree that it needs to be in order to precipitate out with the casein and fat is the whey proteins' effect upon the body and texture of the finished cheese. The denaturing process itself changes the whey protein conformation such that it materially affects the body and texture of the finished cheese. The physical chemistry involved in the coagulation of milk to form cheese is very complex and not fully understood. Anything from simple vibration to the type denatured whey protein will materially affect the coagulation and hence, the yield, as well as the body and texture of the finished cheese.
One solution to handling the cheese whey has been the making of alternate products. Ultra filtration has been tried and has been successful for making a pre-cheese that has been set with rennet to make cheese. Some cheeses have been made this way for over twenty years with market acceptance in various parts of the world. However, when Ultra filtration was used to make mozzarella in the United States, the resulting cheese would not melt and stretch satisfactorily. Thus, the ability to use the cheese whey to develop other cheese products or increase yield has been limited.
The whey protein which cannot be used within the cheese making process must be dried or otherwise processed to remove it from the liquid whey. A commercial whey drier typically costs between about 5 and 10 million U.S. dollars and consumes a significant amount of space and energy. Numerous other systems are also available for separating the whey protein from liquid cheese whey. For example, various mechanisms for separating the whey from the liquid are disclosed in U.S. Pat. Nos. 3,642,492; 3,840,996; 3,873,751; 4,297,382; 4,497,836 and 4,617,861, to name a few. Of course, several such systems may be used in conjunction with one another to separate and dry the whey protein.
Disposal of the whey is difficult because the high protein concentration and high BOD can quickly contaminate wells and local streams and rivers. The high protein concentration can cause algae blooms in surface waters, and can render ground water unusable for many purposes.
While the high protein concentration of the whey has been found to be desirable for use in health drinks and other nutritional snacks, the market are generally insufficient to keep whey protein prices higher than the cost of production. This is due, in part, to the properties of the whey protein. Thus, while cheese solids in mozzarella are currently worth about $2.40-$3.60 (U.S.) per pound, the whey protein sells for about $0.58 (U.S.) per pound. When the costs associated with drying and handling are figured in, the cheese producer usually sells its whey protein at a loss.
In response to this ongoing problem, numerous new products have been developed to utilize the whey protein. For example, U.S. Pat. Nos. 3,642,492 and 3,873,751 teach a method for making a simulated skim milk. Likewise, U.S. Pat. Nos. 4,161,552 and 4,259,363 disclose the use of whey solids in place of non-fat dry milk for making comminuted meats. These products, however, have not been sufficiently successful to create a significant market for the whey protein.
Other companies have specially engineered proteins that are synthesized from the whey proteins. While such specialty proteins make the handling of whey protein profitable, there is a limited demand for such proteins, and the proprietary rights of certain companies limit who may produce the products.
Thus, there is a need for a system that can more effectively utilize whey protein obtained during the cheese making process to thereby increase profitability. Such a system should have little or no negative environmental impacts and should be relatively easy to use. Thus, with the cheese market at $1.80 (U.S) per pound, the most profitable return for whey protein would be to return it to the cheese thereby increasing yield.
In addition to brine and whey protein, ten percent of the butterfat is lost to the whey and is recovered as whey cream. Whey cream is sold as a by-product at a low return. This process returns the whey to the curd for a high return and increased yield.
In addition to brine, whey protein and whey cream, there are several other concerns that limit the profitability of cheese makers. For example, spoilage of cheese is a common problem. As cheese sits in warehouses or on store shelves, mold and/or bacteria can grow on the cheese, thereby making the cheese unfit for consumption. This is especially problematic for fresh cheeses.
It is well known that there are several acids and metabolics of bacteria that interfere with growth of bacteria and the like on cheeses. These substances, include, but are not limited to nisin, MICROGUARD and MICROGUARD PLUS (available from Rhoda, Madison, Wis.), NIPISAN (available from Aplin and Barrett, Beaminster, England), and the ALTA series (produced by Quest International of Hoffman Estates, Ill.). These items are typically referred to as probotic metabolites. By interfering with bacterial growth, the probotic metabolites serve as a shelf life extender and decrease losses due to spoilage. While probotics have been used in other food products, there has been a general inability to effectively add probotics to cheese products. This is because the probotics interfere with the growth of the cheese culture. Currently, the probotics are applied to the surface of the cheese, but no mechanism has been found to infiltrate the cheese to provide consistent improvement in shelf life. Thus, there is a need for a method of manufacturing cheese by which probotics and the like can be added to the cheese products to effectively reduce spoilage.
In addition to providing a mechanism for reintroduction of whey protein into cheese to reduce or eliminate disposal concerns, the method of the present invention enables the probotics to be added after the culture has preformed its necessary functions. Thus, the probotics afford the ability to prevent further culture growth along with the prevention of other growth by spoilage or contaminating bacteria. Contaminating bacteria typically produce off flavors or texture defects such as gassing in cheese. The specially introduced probotics, however, can substantially reduce or eliminate such concerns.
Related to the concern of spoilage is the need for refrigeration. In order to market cheese, the cheese must be maintained at a sufficiently low temperature to prevent spoiling. The costs of electricity alone can be substantial when dealing with high volumes. However, by using probotics in accordance with the present invention, the requirement that cheese be refrigerated can be reduced or even eliminated. If the levels of probotics are sufficient, the only need for refrigeration of cheese comes from the need to maintain the cheese below high temperatures (such as about 90 degrees Fahrenheit) wherein the fats in the cheese start "oiling off".
Yet another problem which has faced the cheese making industry for many years is the desire of many people to purchase low fat or fat free cheeses which have substantially the same body, texture and organoleptic properties as the tradition product. The protein matrix formed by casein in cheese entraps both the moisture and fat globules. The physical structure of the fat prevents the protein from contracting into a hard brittle matrix. However, when fat is removed from cheese, the protein matrix continues to contract during aging and the resulting body and texture does not resemble the fat containing cheese.
In addition to the ability to reintroduce whey protein and add probotics, the present invention allows the infusion of materials into the protein matrix such that the protein web like structure will not contract. If the infused particles resemble the mouth feel and lubricity of fat, then the cheese texture will resemble that of the original cheese product. The fat molecule, however, is critical both to the texture and taste of the cheese product. Currently, most reduced fat cheeses are rubbery and tough and lack the taste of traditional cheese. In light of the increasing demand for low fat foods, it is desirable to develop a system for enhancing cheese which enables the production of low fat cheese which has the body, texture and organoleptic properties of regular cheese.
Still another challenge faced by the cheese industry is the limited ability to produce cheese having selected flavors. Currently there is widespread demand for food products which are both high in nutrition and which have a pleasing flavor. Many of the top selling treats are fruit flavored snacks in which fruit extracts are used. While attempts have been made at developing novelty cheeses having a variety of nontraditional flavors, such have been unsuccessful because cheese will not normally adopt flavors or colors in a consistent manner. Thus, while a flavor may be added to cheese, it may be much stronger in some areas of the cheese than in other areas. This invention allows the incorporation of fruit solids, flavors, and sweeteners into the cheese mass in a consistent manner to thereby facilitate the use of a variety of flavors.
In addition to novelty flavors, there are many cheeses that require prolonged aging or ripening to obtain the desired flavor. Traditionally, penetration of the cheese by the enzymes that ripen the cheese has taken months. Current technology allows the cheese maker to accelerate the ripening of cheese by incorporating the cheese with known enzymes while the cheese is on the finishing table. The enzymes, however, are extremely expensive (i.e. up to seven hundred dollars U.S. per pound) and 25 to 40 percent of the enzymes are lost to the whey. Additionally, uniform distribution of the cheese with the enzymes remains a significant problem. Conversely, defects known as modeling are common with the use of enzymes in the above manner.
A closely related problem with accelerated ripening of cheese is the inability to control the aging process. Once an enzyme has been introduced, the aging/flavor change of the cheese continues. Thus, the cheese continues to age the longer it is on the shelf and eventually becomes too strong for most consumers. Thus, there is a need for a method by which improved control is provided for accelerated aging. The present invention provides the cheese maker with improved control of the accelerated ripening technique on several fronts. First, the method of the present invention allows for improved penetration of the cheese curds with the enzyme used for accelerated ripening. Second, the method of the present invention allows for the same day production of aged cheese by the use of a cheese/enzyme concentrate that is prepared independent of the cheese. Third, in accordance with the principles of the present invention, it has been found that selective inactivation of the enzyme used for accelerated ripening can be used to inhibit over ripening of cheese products made by an accelerated ripening method.
Still yet another problem associated with the manufacture of cheeses is the labor involved in the production. This is especially true for cheeses that are formed, cooled and then grated or shredded into small pieces of cheese. Such is common for cheese that is used by commercial establishments on pizzas. The small cheese particles melt more rapidly on the pizza and prevent excessive browning. However, to form Pizza cheese, the cheese curds are usually formed in the pasta filata process, passed through brine solution to cool, and then grated or shredded. A significant saving could be achieved by reducing the amount of labor, equipment, and waste to form the Pizza cheese particles. This invention only uses one piece of equipment and one process to produce Instant Quick Frozen (IQF) Pizza cheese. Furthermore, the improved Pizza cheese has increased yield and maintains the excellent and controllable properties over the entire shelf life of the cheese.